Аннотация
Chlorophyll b -containing cyanobacterium Prochlorothrix hollandica is characterized by a high content of esterified fatty acids (FA) with 14 and 16 carbon atoms in the membrane lipids. Depending on the conditions of cultivation, the relative amount of myristic (C 14:0 ) and myristoleic (C 14:1 ) acids can reach 35%, and palmitic (С 16:0 ) and palmitoleic (С 16:1 ) acids can reach 60% of the sum of all fatty acids in cells. Monounsaturated FAs are represented by C 14:1 , and C 16:1 with an olefinic bond presumably located in the Δ 9 position. We cloned the gene of acyl-lipid Δ9-desaturase, desC1 , from Prochlorothrix hollandica and characterized its specificity to the length of the substrate using the heterologous expression in Escherichia coli cells adding C 14:0 or stearic (C 18:0 ) acids as exogenous substrates. The results show that DesC1 Δ 9 desaturase generates olefinic bonds in the FAs with a length of 14 to 18 carbon atoms with an approximately equal efficiency. This indicates that the length of the FA chain in P. hollandica is determined by the activity of the FA synthase, and the chain is desaturated at the Δ 9 position nonspecifically relatively to its length.